Shear Localization Influences on Assessment of Deformation Behaviors of Pure Iron in Impact Loading Process

Metallic glasses are amorphous meta-stable solids and are now being processed in bulk form suitable for structural applications under impact loading. Bulk metallic glasses have many unique mechanical properties such as high yield strength and fracture toughness, good corrosion and wear resistance that distinguish them from crystalline metals and alloys. However, only a few studies could be found mentioning the dynamic response and damage of metallic glasses under impact or shock loading. In this study, we employed a small explosive detonator for the dynamic indentation to a Zr -based bulk amorphous metal in order to evaluate the damage behavior of bulk amorphous metal under impact or shock loading conditions. Results were compared with those of spherical indentation under quasi-static and impact loading and were discussed. The interface bonded specimen method was adopted in order to observe the subsurface damage, especially the formation of shear bands induced during indentation under different loading conditions.

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A STUDY ON THE BEHAVIOR OF A THIN STS 304 SHEET WITH A FREE BOUNDARY CONDITIONS SUBJECTED TO IMPACT LOADING

International Journal of Modern Physics B ◽

10.1142/s0217979208050838 ◽

2008 ◽

Vol 22 (31n32) ◽

pp. 5572-5577 ◽

Cited By ~ 1

Author(s):

D. G. AHN ◽

G. J. MOON ◽

C. G. JUNG ◽

D. Y. YANG

Keyword(s):

Free Boundary ◽

Impact Energy ◽

Impact Loading ◽

Three Dimensional ◽

Local Deformation ◽

Drop Impact ◽

Absorption Mechanism ◽

Impact Tests ◽

Deformation Behaviors ◽

The Impact

The objective of this paper is to investigate into impact behaviors of a STS 304 sheet with a thickness of 0.7 mm in a free boundary condition subjected to impact loading by a hemispherical impact head using drop impact tests and the three-dimensional FE analyses. The drop impact tests and the FE analyses were conducted with different impact energy ranging from 37.0 J to 45.7 J. From the results of the impact tests, the influence of the impact energy on the force-deflection curve, the absorption mechanism of the impact energy and deformation behaviors of specimen were examined quantitatively. Through the FE analyses, the variation of stress-strain distributions and characteristics of the local deformation during the impact of the specimen were investigated.

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Microstructures of Laser Processed Fe-Cr Surface Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098150 ◽

1981 ◽

Vol 39 ◽

pp. 328-329

Author(s):

P. A. Molian ◽

K. H. Khan ◽

W. E. Wood

Keyword(s):

Cooling Rate ◽

Pure Iron ◽

Continuous Wave ◽

Laser Surface ◽

Material Surface ◽

Constitution Diagram ◽

Incident Power ◽

Surface Alloying ◽

Laser Surface Alloying ◽

Spot Diameter

In recent years, the effects of chromium on the transformation characteristics of pure iron and the structures produced thereby have been extensively studied as a function of cooling rate. In this paper, we present TEM observations made on specimens of Fe-10% Cr and Fe-20% Cr alloys produced through laser surface alloying process with an estimated cooling rate of 8.8 x 104°C/sec. These two chromium levels were selected in order to study their phase transformation characteristics which are dissimilar in the two cases as predicted by the constitution diagram. Pure iron (C<0.01%, Si<0.01%, Mn<0.01%, S=0.003%, P=0.008%) was electrodeposited with chromium to the thicknesses of 40 and 70μm and then vacuum degassed at 400°F to remove the hydrogen formed during electroplating. Laser surface alloying of chromium into the iron substrate was then performed employing a continuous wave CO2 laser operated at an incident power of 1200 watts. The laser beam, defocussed to a spot diameter of 0.25mm, scanned the material surface at a rate of 30mm/sec, (70 ipm).

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